The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A type of a split rotating seal, widely known as a scarf cut plastic seal, is used in many industries and is manufactured by a large number of companies worldwide. This type of seal is used in modern automatic transmissions to seal shafts and clutch components against the passage of hydraulic fluid, usually transmission fluid. An exemplary scarf cut seal is disclosed in U.S. Pat. No. 7,010,844.
In many cases, a scarf cut plastic seal is made from PTFE compound, short slender fibers of glass, graphite or Kevlar, and a number of additives, the amalgam being a homogeneous mixture of PTFE compound, the fibers and additives. A purpose of the fibers is to reinforce the PTFE compound in order to improve its structural properties or to produce a seal whose functional characteristics are particularly suited to an application of the seal or to the environment in which the seal is intended to function. The additives have a similar purpose.
This type of seal typically has a rectangular cross section and a beveled split or scarf cut having an angle in the range of 7-45 degrees when projected on the longitudinal axis of the seal. This type of seal can be installed in an outer groove formed in the outer surface or journal of a rotating or stationary shaft. Alternatively, the seal can be installed in an internal groove formed in a bore of a rotating or stationary housing.
Scarf cut seals tend to loose their cylindrical form due to radial compression, which results in plastic deformation. They become dislocated in the retaining groove due to clearance between the surfaces of the seal and the groove, and they are susceptible to deformation. These factors cause unintended interference between the installed seal and shaft as the shaft is inserted within a bore. The seal is often cut by the shaft during shaft installation, commonly referred to as a “cut seal” condition. Or the seal is unintentionally forced from its groove by the shaft as the shaft slides in the bore past the installed seal.
Accordingly, it is desirable to provide a jointed seal with improved retention characteristics as compared to scarf cut seals. According to the present disclosure, a locking joint seal includes a ring-shaped body made from PTFE, rubber, thermal plastic material, or other known seal materials, and having a first end and a second end. The first and second ends each include mutually engageable first and second locking features. The first locking feature including a first axially extending portion overlapping a second axially extending portion of the second locking feature in an assembled condition.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.